Access floor panel with edge trim

ABSTRACT

An access floor panel construction employing peripheral trim channel elements joined together at the panel corners and fixed at their mid-lengths to the edges of a main body. As disclosed, the trim elements are of an organic thermoplastic material and are ultrasonically welded together at their ends and thermoplastically deformed into receiving portions of the main body edges. An assembly fixture holds the trim elements in position for final assembly in a manner which reduces the size of any gaps which might occur as a result of dimensional tolerances in the panel components.

This is a division of application Ser. No. 543,508, filed Oct. 19, 1983,now U.S. Pat. No. 4,574,555.

BACKGROUND OF THE INVENTION

The invention relates to access floor panels and, more particularly, toan assembly of such panels which includes distinct peripheral trimmolding.

Prior Art

Access floor panels, ordinarily rectangular, which term as used hereinincludes square, are used, for example, by arranging them in arectangular array to provide an elevated floor in rooms where computerequipment is installed. Throughout the lifetime of the floor, individualpanels can be temporarily removed to service, repair, or otherwise workon wiring, ducting, or the like lying below the floor. Certain types ofknown floor panels have peripheral trim or moldings. These trim elementscan require special forming techniques, such as molding or stamping, andtherefore can be relatively expensive to manufacture and/or assemble.

Typically, an access floor panel has a visible covering in the form of ahigh pressure plastic laminate, vinyl-reinforced tile, carpeting or thelike. In practice, such a cover ordinarily is manufactured withdimensional tolerances that could potentially result in gaps between thecover and the associated perimeter trim. From an appearance standpoint,such gaps are undesirable.

SUMMARY OF THE INVENTION

The invention provides a novel floor panel assembly having perimetertrim that affords improvements in appearance while reducingmanufacturing costs. The construction in accordance with the presentinvention effectively reduces the size, and therefore theconspicuousness, of any gaps between the panel cover and trim. Accordingto the invention, the perimeter trim elements of the panel are assembledaround the panel and are then permanently locked in place. The finalposition of the trim elements relative to the other panel components isdetermined by an assembly fixture which limits the overall dimension ofthe final assembly. The trim elements are first located by the fixtureand are then fixed in position by locking their corners together andtheir mid-lengths onto adjacent areas of the panel body. The assemblyfixture is arranged to allow the trim elements to float between adjacentedges of the panel covering and fixture. The trim elements are therebypermitted to adjust to the actual size of the panel cover in a mannerwhich tends to divide any dimensional short fall of the cover, withintolerance, into two relatively small and, therefore, inconspicuous gaps,one between the adjacent cover edge and a trim strip and one between thetrim strip and fixture.

Ideally, the panel trim elements are plain channels having a generallyC-shaped cross section. The plain C-shape configuration readily lendsitself to manufacture by extrusion, rolling or like economicalfabrication techniques. In assembly with the panel body, the trimchannel is slipped over a peripheral flange on the panel body.Preferably, the trim securing operations are performed on the flange ofthe trim C-section, which is on the reverse or bottom of the panelassembly, so that the original smooth appearance of the front or topface of the trim elements is undisturbed.

In the preferred disclosed embodiment, the trim elements are extrusionsof an organic thermoplastic material, such as vinyl. At the corners ofthe panel, the adjacent ends of the trim elements are thermally fusedtogether at their reverse flanges by ultrasonic welding. In addition, atstrategic locations, the lengths of the trim elements at their reverseflanges are plastically deformed into recessed areas of the panel body.As disclosed, this deformation is accomplished by local ultrasonicheating of the reverse trim flanges. In accordance with the invention,the trim is thus joined into a peripherally continuous unit and fixed tothe panel body at a multiplicity of points without the use of separatefastening means.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an access floor panel constructed inaccordance with the invention;

FIG. 2 is a fragmentary, cross-sectional view of the access floor panel,taken across the plane indicated by the lines 2--2 in FIG. 1;

FIG. 3 is a view of the lower reverse face of the panel assembly priorto completion;

FIG. 4 is a fragmentary view, partly in section, of an edge zone of theaccess panel assembly taken at the plane indicated at the lines 4--4 inFIG. 3 prior to fusion of adjoining ends of two adjoining trim elements;

FIG. 5 is a fragmentary view similar to FIG. 4, but with only the cornerzone of the trim elements in section, and taken after fusion of theadjoining trim ends;

FIG. 6 is a fragmentary, cross-sectional view of the panel assemblytaken across the plane indicated by the lines 6--6 in FIG. 3, where thepanel trim element has been locally fixed to the perimeter of the panelbody;

FIG. 7 is a view similar to FIG. 6 illustrating a modified form of thepanel body;

FIG. 8 is a view similar to FIG. 6 illustrating a second embodiment ofthe invention; and

FIG. 9 is a somewhat schematic, perspective view of an assembly fixturein which an access panel is being assembled.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings, and in particular to FIGS. 1 and 2, thereis shown an access floor panel assembly 10 for use in an elevated floorsystem. The illustrated panel consists of a main panel body 11, acovering 12, and peripheral trim molding elements 13.

In the illustrated case, the main panel body 11 is a sheet metalfabrication comprising a bottom pan 16 and an upper sheet or plate 17.The bottom pan 16 is stamped or otherwise formed with peripherallyoutwardly directed flanges 18 that extend along sidewalls 19 and subtendan area substantially equal to that of the top sheet 17. The top sheetis a simple planar metal sheet. The pan 16 and top sheet 17 arepermanently assembled, for example, by spot welding the flanges 18directly to the underside of the top sheet, where, as shown, the pan andtop sheet are constructed of steel. In customary fashion, the finishedaccess floor panel 10 is square, with each side, including the trimelements 13, being nominally two feet long.

The cover 12 provides an upper surface 12 which is the visible wearsurface of the panel 10. The cover 12, typically, is a high pressureplastic laminate, vinyl-reinforced tile, carpet tile, or other knownfloor covering. The cover is preferably adhesively fixed to the uppersurface of the panel sheet 17 prior to assembly of the trim elements 13.A trim or molding element 13 preferably is formed from a plain extrusionwith a generally C-shaped block cross section. A suitable material forthe trim 13 is a thermoplastic material, such as vinyl, which has atleast some degree of resilience. In the illustrated case, a lower orbottom one of the flanges, designated 22, of the trim C-section issomewhat longer than the other or upper flange, designated 23. A web 24of the C-section has a length approximately equal to the combinedthickness of the pan top sheet 17 and flange 18. In a free state, thecross section of the trim can be arranged so that the flanges 22, 23converge slightly in a direction away from the web 24 so that when theseflanges are assembled over the periphery of the main body 11, they canresiliently grip the surfaces of the pan flange 18 and top sheet 17.

In the illustrated embodiment, the individual trim elements on each edgeof the main body 11 are identical. The trim elements 13 are cut in sucha manner that the visible upper side (FIG. 1) may give the appearance ofa butt joint at each corner of the panel assembly 10. As can be seenfrom study of the lower half of FIG. 3 and of FIG. 4, the trim elements13 are cut at one of their ends (arbitrarily termed the "head end" forpurposes of this description) across spaced, transverse planes, and attheir opposite ("tail") end across a single plane.

The trim elements 13 are assembled around the perimeter of the mainpanel body 11 and joined head-to-tail. It will be understood that thetop sheet 17 and bottom pan 16 have been previously welded together. Ateach corner of the main panel body 11, the lower flange 22 of the headend of a trim element 13 is slipped over the lower flange 22 of the tailend of the adjacent trim element 13 (FIG. 4).

With the trim elements 13 provisionally assembled on the panel body 11as just described, these members are positioned in an invertedorientation on a gaging and assembly fixture 26, illustrated in FIG. 9.The fixture 26 comprises a horizontal base 27. Fixed on the base 27 aretwo elongated side gage blocks 28 precisely disposed at right angles toone another. Another pair of mutually perpendicular blocks 29 areseparately slidably mounted on the horizontal base 27. Each of themovable blocks 29 has a linear actuator 31 associated with it. Eachactuator 31 has a longitudinally movable shaft 32 fixed to itsassociated block 29. Upon energization of an actuator 31, its shaft 32extends horizontally to move the respective block 29 towards an oppositefixed block 28, or retracts horizontally to move its block away from theopposite fixed block.

In the retracted positions of the actuators 31 (illustrated in FIG. 9),the blocks 29 provide sufficient clearance to freely receive the mainpanel body 11 and trim elements provisionally assembled thereon in arectangular space bounded by the blocks 28, 29. When the actuators 31are extended, inner vertical surfaces 33, 34 of the blocks 28, 29 definea precise square, ideally, equal to the exact nominal size of thefinished panel assembly 10. The exact extended position of the blocks 29can be adjusted, for example, by limiting extension of the shafts 32,such as by adjusting the location of the bodies or the actuators 31 andfixing such actuator position by tightening bolts 36 on flanges 37 fixedto the actuators. The actuators 31 can be power driven, for example,pneumatically, hydraulically, or electrically.

Disposed above the fixture base 27 is a trim securing platen 41 of theassembly 26. In the illustrated example, the platen device 41 issuspended on the vertical shaft or rod 42 of an actuator 43. The platenactuator 43, in turn, is fixed relative to the base 27 by a suitableframework (not shown). Operation of the platen actuator 43, poweredpneumatically, hydraulically, electrically, or by other suitable means,causes its shaft 42 to be displaced longitudinally along its verticalaxis. In a retracted position, as shown in FIG. 9, the platen 41 andelements carried on it are vertically displaced from the base 27 asufficient vertical distance to allow free movement of the provisionallyassembled panel body 11 and trim elements 13 horizontally between theplaten-mounted elements and blocks 28, 29.

The platen 41 has a generally rectangular or square configurationcorresponding to that of the access floor panel assembly 10. Mounted onthe periphery of the platen 41 are a plurality of ultrasonic units 46,47, and 48. The units 46-48 each include an ultrasonic transducer orgenerator 51, 52 and a work-engaging tool 53, 54, and 55. At the cornersof the platen 41, the work-engaging tool 53 has a relatively broad, flatworking surface 57 which lies in a horizontal plane. The corner tools 53are aligned with, i.e., overlie, the corners of the panel body 11. Alongeach side of the platen 41, two transducers 51, 52 each drive tools 54,55 with two or three work-engaging pins 58. Where, as shown, the tools53-55 are fixed (except for ultrasonic vibrational displacements) on aplaten 41, the lower ends of the pins 58 of all of the tools 54, 55 arecoplanar, and the working surfaces 57 of the corner tools 53 arelikewise coplanar with each other. The work-engaging pins 58 lie in aplane slightly lower than the plane of the corner tool working surfaces57. As indicated in FIG. 9, the corner tools 53 lie directly over thearea in which the trim flanges 22 are overlapped. The tool pins 58 lieover predetermined points along the mid-lengths of the bottom trimflanges 22.

The trim elements or strips 13, already provisionally assembled on themain panel body 11, manually or otherwise as previously described, andloaded on the assembly fixture 26, manually or otherwise, within thespace surrounded by the blocks 28, 29, are permanently secured to thepanel body 11 in the following manner. In response to actuation bysuitable controls (not shown), the actuators 31 are energized to extendtheir shafts 32, causing the movable blocks 29 to move towards theirrespective opposed stationary blocks 28 and effectively constrain thetrim elements 13. As previously indicated, the movable blocks 29, whenextended, define with the stationary blocks 28 a precisely dimensionedcavity, bounded by the vertical block surfaces 33, 34, which issubstantially equal to the finished nominal size of the access floorpanel assembly 10. Where the cover 12 is undersized but withintolerance, the trim elements 13 will naturally tend to find an averageposition midway between the adjacent block surfaces 33, 34 and verticaledges 61 of a cover. This floating action of the trim, allowed bylimiting the inward extension of the movable blocks 29, tends to averageout or reduce any gap which might otherwise exist between the peripheryof the cover 12 and confronting portions of the upper flanges 23. Itwill be understood that the thickness of the trim web 24 in relation tothe outside overall length of the top plate 17 and flanges 18 is suchthat these latter members do not restrict the inward horizontal movementof the trim elements 13 when the movable blocks 29 are closed orextended towards the stationary blocks 28.

With the main panel body 11 and trim molding elements 13 constrained intheir desired permanent relation as described above, the platenacutuator 43 is energized to cause the platen 41 to descend until thetools 53-55 engage respective underlying areas of the trim flanges 22.At this time, the ultrasonic transducers 51, 52 are energized to impartsonic energy to the work-engaging tools 53-55. At the corners of thepanel body 11, the tool-working surfaces 57 fuse the overlapped flangeportion 22a into and flush with the underlying flange 22 of theadjoining trim element 13, as is indicated in the changes in conditionof these areas from that illustrated in FIG. 4 to that illustrated inFIG. 5.

Simultaneously with fusion of the trim corners, the work-engaging pins53 ultrasonically heat and permanently thermoplastically displace localareas of the midsection of the lower flanges 22. With reference to FIGS.3 and 6, it will be understood that recesses 66 in the form of small,round holes are previously formed in the pan flanges 18. These recesses66 are in vertical alignment with the work-engaging pins 58 so thatmaterial 67 plastically displaced by these pins, upon descent of theplaten 41, is received in these recesses 66. The material 67 whichprojects into the plurality of recesses 66 along a side of the panelbody permanently retains the trim 13 on such side precisely at theposition at which it is held by the gaging blocks 28, 29.

FIG. 7 illustrates a modification of the invention wherein the top sheet17' is provided with recesses 68 in the form of circular holes inregistration with the holes 66 of the bottom pan 16. In this case, theultrasonically displaced material 67 is received in both recesses 66,68, where a more positive locking of the trim elements 13 to the panelbody is desired or necessary. To ensure that material of the trim flange22 is plastically deformed into both recesses 66,68, the workengagingpins 58 can be provided with additional lengths beyond that which isutilized in the arrangement of FIG. 6.

FIG. 8 illustrates another embodiment of the invention. Like thearrangement disclosed in FIG. 7, the bottom pan flanges 18 are providedwith holes 66 and the top sheet 17 is provided with aligned holes 68. Inthis embodiment, unlike the prior described arrangements of FIGS. 6 and7, the trim elements 13' are formed with apertures 69 aligned with theseveral holes 66, 68 at each side of the main panel body. Into each ofthese holes 69, there is assembled a pin 71. The pin 71 can be sized tofit snugly in the panel body holes 66, 68, and the hole 69 in the trimflange 22' can be somewhat oversized. After assembling the main panelbody and trim 13', the pins 71, which are formed of a thermoplasticmaterial thermally weldable to that of the trim elements, can beassembled into the holes 66, 68, 69. The pins 71 can have original axiallengths somewhat greater than that illustrated in FIG. 8, so that, uponoperation by the work-engaging pins 58 or their equivalent, the pins 71are expanded in the manner of a rivet to fill the oversized trim flangeholes 69 and account for any eccentricities between the pins 71 and thecenter of the holes 69.

Although the preferred embodiments of this invention have been shown anddescribed, it should be understood that various modifications andrearrangements of the parts may be resorted to without departing fromthe scope of the invention as disclosed and claimed herein.

What is claimed is:
 1. A method of making an access floor panel whichcomprises the steps of providing a rectangular main body with edgeshaving lengthwise actual dimensions and corners formed by the edges, anda set of four trim elements having ends and lengths corresponding to thedimensions of the edges of the main body and C-shaped cross sectionswith space between top and bottom flanges to fit over edge portions ofthe main body, assembling the trim elements around the main body withthe top and bottom flanges of each element straddling an associated edgeof the main body, locating the trim elements in a rectangular patternaround the main body in a manner that allows the elements to takepositions closer to the nominal dimension of the finished panel than ispermitted by the actual dimensions of the main body, the bottom flangesof the trim elements thereafter being permanently deformed along theirlengths into receiving portions of the main body to permanently lock thetrim elements in position on the main body.
 2. A method as set forth inclaim 1, wherein ends of the trim elements are welded together at thecorners of the main body.
 3. A method as set forth in claim 2, whereinsaid trim element ends are thermally welded together.
 4. A method as setforth in claim 1, wherein said trim elements are formed of an organicthermoplastic material.
 5. A method as set forth in claim 1, whereinsaid bottom flanges are permanently deformed through application ofthermal energy.
 6. A method as set forth in claim 1, wherein said trimelements are temporarily constrained by a rectangular fixture to sizethe assembly of the trim elements and main body while said bottomflanges are being permanently deformed into said main body receivingportions.
 7. A method as set forth in claim 6, wherein the ends of saidtrim elements are thermally welded together while said elements areconstrained by said fixture.
 8. A method as set forth in claim 12,wherein the bottom flanges are permanently deformed and the ends of saidtrim elements are welded by ultrasonic tool elements.
 9. A method as setforth in claim 8, wherein said ultrasonic tool elements are energized toweld said trim element ends together substantially simultaneously withthe permanent deformation of the trim bottom flanges.
 10. A method ofconstructing an access floor panel comprising the steps of providing asubstantially planar rectangular main body with peripheral edges and aset of four trim channels in the form of plain extrusions of organicthermoplastic material and of C cross section, positioning the trimchannels each on one edge of the main body with portions of such edgesbeing received in a space between top and bottom flanges of theassociated trim channel, restricting the positional freedom of the trimchannels mounted on the main body by a rectangular assembly fixturehaving a pair of mutually perpendicular retractable and extendiblesurfaces adapted to engage the corresponding trim channels, while thetrim channels are restricted by the assembly fixture to a predeterminedposition independent of the actual size of the main body thermallyfusing adjacent ends of the trim channels at the corners of the mainbody and thermoplastically deforming local regions of mid-lengths of thebottom flanges of the trim channels into recesses preformed on the mainbody adjacent its peripheral edges.
 11. A method as set forth in claim10, wherein said fusing and thermoplastic deformation are performed withultrasonic tools.
 12. A method as set forth in claim 11, wherein saidfusing and thermoplastic deformation are accomplished substantiallysimultaneously.
 13. A method as set forth in claim 10, wherein saidmutually perpendicular surfaces are limited in their extension towardssaid main body and channels to a position corresponding substantially tothe nominal dimension of the access floor panel whereby said channelsare allowed to float between the surfaces of the assembly fixture andthe main body to average out dimensional tolerances in components of themain body.